In 地震学在美国，科学家们通常只有少量的传感器用于探测地震. This is one reason why measuring vibrations through the Earth’s surface is an uneven, “危险的”风险. 也, some seismically-active areas have many sensors on h和, while places distant from shifting tectonic plates may have very few. 这种设备的变化使得测量地震振动变得困难, 例如, 水力压裂引发地震. 使用新方法, users could turn each 光缆 length of a few feet into an individual 地震传感器.
在这个新的实验中，研究小组“借鉴”了其他已经开发出的团队 分布式声传感 (达斯)方法. In 达斯, laser pulses are used to detect minute vibrations along optical 纤维/电缆. Researchers insert units called interrogators along the optical 纤维/电缆. These interrogator units send out 和 sense short infrared laser pulses. 由地震活动触发, 光纤上的微小张力导致一些激光被反射，然后反弹回传感器. 通过发送快速脉冲，科学家们可以探测到光散射随时间的变化. By knowing the speed of light, they can pinpoint where the activity occurred.
“真实世界”测试
通过这项最新技术，研究人员基本上在现实世界中测试了达斯方法. 他们把审讯者的电源接通 光缆 line along the Department of Energy’s Dark Fiber Testbed. 绵延13000英里的 电信光纤 在美国西部.S. 用于测试新的通信设备. The researchers targeted a 17-mile cable segment near West Sacramento, 加州, 并记录了7月28日的数据, 2017, 到1月18日, 2018.
研究小组成功地记录了声波在地球上传播的速度信息. In fact, during September 2017, they detected 和 measured the massive 8.1 magnitude earthquake in Mexico (the strongest quake to hit Mexico in a century).
Unfortunately, this detection technique isn’t ready to be used beyond research. But keep an eye open for possible use in the future!
2013年，美国间谍爱德华·斯诺登(Edward Snowden)被捕.S. 国家安全局承包商, 泄露的文件显示，情报机构正在监视普通公民的数据. One disturbing fact was that the spies tapped into 光纤电缆 to access the huge amount of data moving through these cables.
斯诺登的泄密促使研究人员利用量子科学使这种黑客攻击成为不可能. 最后，有进展的报告.
量子密钥分发方法
A startup called Quantum Xchange will access 500 miles of 光缆 沿着U东部.S. 海岸. 量子公司将使用这条电缆创建该国首个量子密钥分发(QKD)网络.
量子交换的“QKD方法”将发送以比特为单位的编码信息，同时以量子比特的形式传输解码密钥, 或量子位元. Usually in the form of photons, the qubits travel easily along 纤维 cables. 然而, any attempt to spy on a qubit would instantly destroy its fragile quantum state, erase any data 和 leave the mark of an intrusion.
一个可能的问题是，“可信节点”必须用于长距离发送量子密钥. These nodes act as repeaters to boost signals in a typical 数据电缆. Quantum Xchange plans to have 13 trusted nodes along its entire network. At these node points, keys are first turned into bits. Then, they are changed back to a quantum state to be sent on. 换句话说，黑客理论上可以窃取这些比特，因为它们暂时是易受攻击的.
Quantum teleportation would use entanglement to eliminate the risk of hacking. Entanglement creates a pair of qubits (usually photons) in a single quantum state. 一个光子的变化会立即影响连接的光子，即使它们相距很远. Therefore, in theory, it should be impossible to hack 数据传输 使用纠缠. This is so because tampering with one of the qubits would destroy both quantum states.
然而, the entanglement method is still confined to research labs. And there are huge challenges to making this approach work in the real world. 据博士说. 芝加哥大学的David Awschalom说, creating 和 maintaining entanglement would be extremely difficult over a 长途光纤网络.
Dr. Awschalom is leading the project involving the university 和 the national labs. 目标是让测试平台使用“即插即用”的方法，让研究人员实验和评估纠缠和传输量子比特的不同技术.
美国.S. Department of Energy will provide several million dollars to fund the test bed. This test bed will use a 30-mile stretch of installed 光缆 between the labs. Members of the Chicago Quantum Exchange will operate the test bed 和 project. This Exchange consists of 70 scientists 和 engineers from the three organizations.
Engineers at the 加州 Institute of Technology have created the world’s smallest 光纤陀螺仪帮助导航. 这种新型陀螺仪比普通陀螺仪小500倍，可以装在一粒米上. 与机械装置相比，这一研究突破可能会带来更精确的光纤陀螺.
什么是光学陀螺仪
Advanced 纤维 optic navigation technology is critical for aircraft, 导弹, 无人驾驶飞行器和地面车辆. These machines 和 other platforms depend on 光纤陀螺仪s to operate safely.
它们是如何工作的?
A 光纤陀螺仪 detects changes in position or direction using the 萨尼亚克效应. In this way, an optical gyro functions similarly to a mechanical gyro. 然而，光陀螺的工作原理是利用光通过一圈光纤.
在一个典型的光学陀螺仪内部，一根缠绕的光纤携带激光脉冲. Some pulses move clockwise 和 others go counterclockwise. 陀螺仪通过检测这些脉冲到达传感器的微小变化来测量旋转. Researchers have tried to create smaller optical gyros. 然而, 随着陀螺仪尺寸的缩小, 来自传感器的信号变得越来越弱，直到被散射光的“噪音”淹没.
团队做了什么
The Cal Tech research team designed a low-noise, photonic gyroscope. They etched light-guiding channels onto a two-square-millimeter silicon chip. These channels guide the light in each direction around a separate circle. This layout keeps scattered light from confusing the device’s sensors. The new design also reverses the light’s direction from time to time. This change helps to cancel out much of the related “noise.”
利用Sagnac效应来测量旋转的光学陀螺仪最终可能被小型化到纳米光子平台上. 然而, 热波动, 元器件漂移和制造不匹配往往限制了这些陀螺的信噪比. Because a microscale unit would have a weaker signal, researchers have not yet created an integrated nano-photonic 光纤陀螺仪.
To support the exponential growth of global data traffic, 100 Gb/s submarine transmission systems are being installed in transoceanic links. 这些系统使用c波段掺铒光纤放大器(EDFA)在单芯光纤上提供高达~ 10tb /s的容量。.
在SubOptic 2016上发表的一份新白皮书中, OFS和OFS实验室的研究人员讨论了关键的光纤和放大器技术，帮助用户实现海底传输系统的高容量和长覆盖范围. These technologies include ultra-large-effective area, low loss optical 纤维s 和 their impact on performance, 以及中继和无中继潜艇系统的关键放大技术.
研究人员希望利用未使用的网络, 暗光纤电缆有助于探测地下声波，可以预警即将发生的地震.
Engineers at the 加州 Institute of Technology have created the world’s smallest 
